Oh my, forgotten golf star roars to life at the Open

The 28-year-old former world amateur champion earned a meagre $US7,414 ($A11,400) on the secondary Epson Tour in 2024 before turning to Ritchie Smith, the revered coach of Minjee and Min Woo Lee and Australian No.1 Hannah Green, Oh's best mate.

Ending Round 1 with a birdie to take the outright lead ��#AusOpenGolf pic.twitter.com/zhrehIky6R— Golf Australia ⛳� (@GolfAust) November 28, 2024

"I can actually somewhat hit it somewhere where I'm looking at it," Oh said when asked how Smith had helped her after missing five straight cuts in the US.

"He's very supportive and he knows a thing or two obviously with the players that he already has.

"It's been good to like kind of rebuild and I've known Richie for a long time so I think that level of comfort has been there."

After playing her first Australian Open at age 12, Oh has now positioned herself nicely to reverse her fortunes in stunning fashion with a first victory in more than two years.

South Korean amateur Hyojin Yang, who only qualified on Monday, matched Oh's seven-under round with a 65 at neighbouring Victoria to share the lead.

Pre-tournament favourite Green is lurking ominously just one shot back in third after opening with a six-under 67 at Kingston Heath.

The world No.6 was even through eight holes before bursting to life with six birdies in the last 10.

"It was not my best start, but obviously it was nice through the back nine to make some good birdies on some tough holes," Green said.

Rising star Justice Bosio is outright fourth at five under, while Steph Kyriacou shook off two back-nine three-putts to card a four-under 68 at Victoria.

A major runner-up at this year's Evian Championship in France, Kyriacou had six birdies and is tied for fifth with New Zealander Hanee Song, Taiwan's Chun-Wei Wu and Thailand's Kornkanok Sungpankhao, who all started at Kingston Heath.

"I hit it pretty good. Honestly, I did everything well today," Kyriacou said.

"The couple of bogeys I made, I just hit it in one terrible spot and then I just had a three putt, so nothing to stress about.

"I'm feeling good about this week."

Steph Kyriacou crushes a fairway wood on day one of the Australian Open in Melbourne. (Con Chronis/AAP PHOTOS)

Playing with Kyriacou, travel-weary superstar Minjee Lee could only manage a two-over 74 to languish eight shots off the pace.

The dual major winner and former world No.2 missed a series of short putts and blamed a lack of sleep and no coffee before teeing off early after only arriving from Florida on Wednesday.

"It was a short sleep. I'm pretty tired and was yawning quite a lot," Lee said.

"I probably wasn't quite 100 per cent on, but there's always tomorrow so hopefully I can make up for all the missed putts that I had today."

South Africa's two-time defending champion Ashleigh Buhai rallied from three over early to post an even-par 73 at Kingston Heath to remain an outside chance of pulling off an unprecedented Open hat-trick.